Electric circuit breaker



Jan. 18, 1955 w. A. THOMAS ELECTRIC CIRCUIT BREAKER Original Filed Aug. 16. 1950 INVENTOR. 4/4/14 A. f/mms By /W Arromvey United States Patent ELECTRIC' CIRCUIT BREAKER William 'A. Thomas, Plainvilie," Conny assignol" to General Electric Con1pany, a corporationof New York Original applieation August 16, 1950,"Serial No.'179,692, now "Patent No. 2,627,563, dated February 3, 1953. Di'vitledand this application' september 4,1951, Serial 'No. 244,897

" 4 Claims. "(CL 200--144) My invention relates. particularly to a' breaker adapted for use in panel boards or 'likeconstructions.

This 'is a -division from =-application :Serial Number I79,692,'filedAugust 16,1950, now Patent'No. 2,627,563, dated February 3, 1953, in which the circuitbreaker per se is more fullyset forth and claimed.

"The above ideutified application is directed to a simple and compact breaker which may-'be operated to open or close 'a circuit manually and" which can" be reset man- .ually after automatic opening of the circuit. :The circuit breaker is provided *with both thermal-and' magnetic tripping mechanisms toi provide for -automatic circuitinterruption uponthe occurrence of continuous over- "loads' of agiven value or upon instantaneous overloads of a much higher-value.

The present application isdirected particularly 'to' the stationary contact and terminal assembly" and: its mountingwith respect to-the casing -and arc" chute.

- It is an-important object of the present'invention to provide an improved structure of-this type 'which facilitates assembly; reduces the costof manufacture, and provides forf'pluggingin 'of 'the circuit 'breaker to the "busses of panel boards or similar equipment.

Y Further objects I and advantages :will become apparent from the following description taken in connection with the accompanying drawingin which:

"Fig. lisa side view of the' inside -of a cir'cuit breaker embodying 'my invention"showing the parts in closed circuit'positionand showing an arcchute in cross-section.

'Fig. -2- is an' edge'view' partly in sectionshowing the line terminal.

Fig. 3 is a view: similar to Fig.- l showing'the parts the position they occupy "when tripped automa'tically.

Fig. 4 is a view of the righthand edge of the housing showing the load terminal.

-Figi5 is a' fragmentary. plan'=and section on'the plane of the line 55 of- Fig. 3.

Fig. 6 is a view on a smaller scale showing how two of the 'circuit breake'rsare' mounted on a'panel board.

The breaker mechanism is--mounted within a rectangular housing formed of insulating material. The two parts of -the housing 7' and 7' are secured "together jby-screws" or rivets-8,--8, 8. The'stationa'ry switch contact 9- is mounted -nearone-edge ofthe housin g and is carried by a lug bent-inwardly and-downwardlyfrom-one end of the main line terminal 10. This terminal consists of a substantially horizontal head plate 11 having spring jaws extending downward from opposite sides and adapt ed to receive between them a terminal stab or blade S carried by a panel board. To reinforce the spring action of the terminal jaws I may provide a spring clip which embraces the two jaws and biases them into contact position.

The housing is provided with a slot 12 in the lower corner formed by the bottom wall and left-hand end wall or flange 14 to allow for the introduction of a terminal. stab as will hereinafter be seen. The edges of the jaws of the terminal 10 abut against the flanges 14 of the housing adjacent the slot 12 and the head of the terminal 10 is cut away to fit the lug 14 which positions the terminal in the housing, while the lower ends of the jaws are adjacent the slot in the bottom wall. Above the head of the terminal I provide a barrier plate 15 formed of insulating material and which is positioned by the flange 16 which projects inwardly from the edge wall of the housing. The barrier plate extends across the upper ends of the side walls of the arc chute.

2,700,086 Patented Jan. .18, 1955 The are chute 18 is formed of suitablefireproof material' and it is providedwith two substantially parallel rectangularside walls joinedby two end walls at right angles to each other,-the bottom'end' wall resting'on the 5 bottom flange 19 of the housing part 7, 7. The-upper --rear -edge 20 of the-arcchute extends between the lug and theedgesof the contact jaws, with the lug and contact 9 between the side walls-of the arc chute,-so-that the -edge 20-is positionedby the-contact carrying lug of the 10 terminal- 10 while the lower edge of thearc chute" is positionedby the lug "-21-which2projectsupwardly from the bottom-flange of the housing.

"An-outlet from the are chute is provided by' the passage 22 which may have restricted-sections as-shown in 15 Figures 1 and 3 and an outlet or discharge opening 23.

- The load terminal- 24 may beof suitable form carried by a-bracket- 25- which: is clamped: tonne-housing by 1 a screw 26. The-calibrating screw 27 .is adjustable in the nut 28-and coacts-with a bendable; part 29-05 the brack- The thermally responsive bimetallic strip 30 is secured atoneend to the bracket 25. A- latch memberfil has a pivotal bearingi32 in the housing'adjacent the bimetal -strip 30. The other end of the-latch member 3l has'a 25 hook portion-33-which istpressed again'st the tip of the "bimetal strip by a spring- 34 which presses against the abutment 35.

-The-cradle or-tripping-membcr 36 has a-pivotal bearing-37 in the housing-and normally engages thelatch 30 38 ot membei ii. The movable switch-m'ember-SQ is hingeddna bearing w of the cradle 36 and has a contact 41 adapted to co-act with the stationary contact 9.

The actuating lever-42 is hingedor-pivoted in a-bearing 43 in the housing and provided with'a manually operable piece-44*which-is adapted-to move in a-slot 45 in the face of the housing.

Spring 46; connects the =upper end-of thelever-42 with a lug -47 on the swinging switch member- 39. Normally: the spring biasesthe actuating lever'so' that 40 its lug 48; presses against-thestop sh0ulder'49 in--the housing-and the switch member 39 is biased to a closed circuit positron. I

- A flexible low-resistance conductor50- connects-the gtip of the bimetal member and the movable contact end 45 410i the switch memberfill.

To -manually operate the circuit breaker from r the closed circuit position-of Figure l to an open circuit-position it is merely necessary tomove the finger piece '44 'from the left toward the right whereupon the spring in the conventional toggle action-manner will-throw:the switch member to the right where it willabut against 'a: stop. The contact at the; lower end of the switch member is covered-bythe insulating-plate-lS at the upper edge' of thearc chute so thatthearcin opening the circuit'is confined beneath the plate 1'5-within the chute. .In case of a-prolonged 'smalloverload above the rated capacity-of=-the breaker the-bimetal member 13 will be warped-tromthe positionof-Figure- 1 -so that its lower end will engage the hook 33 of the latch '31 and retract the catch 38 trom'the t ip-of the tripping cradle 36. When thus released the tripping member will take up the position shown in Figure 3 because of the pull of the spring which thrusts the switch member 39 up wardly and thus tilts the cradle anticlockwise until the cradle abuts against the stop 51 in the housing.

To re-set the circuit breaker the finger piece 44 is moved from the central indicating position of Figure 3 toward the right so that the lug 48 on the actuating lever 42 engages the edge 52 of the tripping cradle and thus causes the tip of the cradle to slide down the catch 38 until the parts are interlocked as shown in Figure l with the switch in open circuit position.

By forming the latch member 31 of suitable magnetic material it may serve as an armature effected by the 5 field of a heavy overload passing through the bimetal strip 30 and act to open the circuit in the same manner as above described.

In Figure 6 I have shown two breaker units mounted edge to edge upon a central stab S of the panel board so such as shown and claimed in application Serial Number 274,749 filed by William I. Fleming on March 4,

a 1952, which is a continuation-in-part of application Serial Number l84,759 filed September 14, 1950, assigned to the same assignee as this application.

In such a construction bus bars A, B and C are suitably insulated and mounted within a pan or tray-T and each bus bar provided with a terminal stab or blade S. Each edge of the tray is provided with a hook H adapted to interlock with the lug or flange 54 at the edge of the housing opposite the terminal 10. According-to such a construction it is possible to greatly reduce the size of the breaker unit and panel board construction.

T o mount a breaker unit on a panel board it is merely necessary to engage the edge flange 54 of the housing with a hook at one edge of the panel board and swinging the breaker unit about the hook as a pivot engage the central stab S to provide the desired phase connection. Obviously a breaker unit may be readily detached in the reverse order.

Iclaim:

1. In a circuit breaker, an insulating housing containing switching mechanism and having a bottom wall, an integral terminal and contact supporting member in said housing comprising a substantially horizontal head plate having cooperating contact jaws extending downward respectively from two opposite sides thereof and having a contact supporting lug extending downward from one end thereof in spaced relation with the edges of said contact jaws, a stationary switch contact on the side of said lug opposite said contact jaws, an arc chute provided with spaced side walls of insulating material joined by at least one end wall extending between said contact jaws and said lug with said lug positioned between said side walls, means for positioning said contact jaws and arc chute in said housing with said jaws adjacent and substantially at right angles to said bottom wall, said bottom wall being provided with an opening communicating with said contact jaws, and said mechanism including a switch member movable between the walls of said are chute into engagement or disengagement with said stationary contact.

2. In a circuit breaker, an insulating housing containing switching mechanism and having bottom and end walls forming a corner, an integral terminal and contact supporting member in said corner comprising a substantially horizontal rectangular head plate havingcooperating contact jaws extending downward respectively from two opposite sides thereof and having a contact supporting lug extending downward from one end thereof in spaced relation with the edges of said contact jaws, a

stationary switch contact on the side of said lug opposite said contact jaws, an arc chute made of electrically insulating material provided with substantially parallel spaced side walls joined by two end walls substantially at right angles to each other, one of said walls extending between said contact jaws and said lug with said lug positioned between said side walls, means in said housing for securing said contact jaws and are chute in said corner of said housing with said jaws adjacent and substantially at right angles to said bottom and end walls, said housing being provided with a slot in said bottom and end walls communicating with said contact jaws, and said mechanism including a switch member movable between the walls of said arc chute into engagement or disengagement with said stationary contact.

3. In a circuit breaker, a two-part rectangular insulating housing containing snap action switching mechanism, an integral terminal and contact supporting member in said housing comprising a substantially horizontal rectangular head plate having cooperating contact jaws extending downward respectively from two opposite sides thereof and having a contact supporting lug extending downward from one end thereof in spaced relation with the edges of said contact jaws, a stationary switch contact on the side of said lug opposite said contact jaws, an arc chute made of electrically insulating material provided with substantially parallel spaced side walls joined by at least one end wall extending between said contact jaws and said lug with said lug positioned between said side walls, projections on said housing parts for securing said contact jaws and are chute in said housing with said jaws substantially parallel with a side wall of said housing and adjacent a bottom wall of said housing, said bottom wall being provided with an opening communicating with said contact jaws and said mechanism including a switch member movable between the walls of said arc chute into engagement or disengagement with said stationary contact.

4. In a circuit breaker, a two-part rectangular insulating housing containing snap action switching mechanism, an integral terminal and contact supporting member in a lower corner of said housing comprising a substantially horizontal rectangular head plate having cooperating contact jaws extending downward respectively from two opposite sides thereof and having a contact supporting lug extending downward from one end thereof in spaced relation with the edges of said contact jaws, a stationary switch contact on the side of said lug opposite said contact jaws, an arc chute made of electrically insulating material provided with substantially parallel spaced substantially rectangular side walls joined by two end walls substantially at right angles to each other with the remaining two ends open, one of said walls extending between said contact jaws and said lug with said lug positioned between said side walls, projections on said housing parts for securing said contact jaws and are chute in said lower corner of said housing with said jaws substantially parallel with a side wall of said housing and the end and one edge of said jaws respectively adjacent bottom and end walls of said housing, said housing being provided with a slot in said bottom and end walls communicating with said contact jaws, a barrier of electrically insulating material in said housing positioned above said head plate and extending over the adjacent open end of said are chute, said housing being provided with an arc discharge opening communicating with the other open end of said are chute and said mechanism including a switch member pivotally movable between the walls of said are chute into engagement or disengagement with said stationary contact.

References Cited in the file of this patent UNITED STATES PATENTS 2,467,653 Berthier Apr. 19, 1949 2,490,514 Favre Dec. 6, 1949 2,502,537 Speck Apr. 4, 1950 2,551,822 Bingenheimer et al. May 8, 1951 

